Desktop Video: DTV Switchers and SEGs

Last month we looked at the DTV computer as a source of titles and graphic overlays. In this fourth article in the series, we’ll discuss add-in DTV cards that are similar to overlay cards, but much more sophisticated. They take two or more analog video signals, digitize them, and combine or “mix” them in real time to provide wipes, dissolves, and digital video effects (DVEs).

There are two main types of equipment that perform these functions: switchers and special effects generators (SEGs). Today, most boards combine both of these functions; many include the graphics and title overlay features discussed last month. Though you must add in the cost of the computer, you still come out ahead. The DTV computer will have many other valuable uses, such as logging, scheduling, budgeting, and most important, edit control functions.

We’ll take a look at three of the most popular computer-based SEG/switchers; an overview of their features will give you valuable insight into the product class as a whole.

White, Wheat, or Rye?
The most popular of the computer-based DTV switchers is the Emmy-award winning NewTek Video Toaster. With over 35,000 units sold, the Toaster is easily the most successful product in the history of desktop video. In spite of the Amiga’s success, however, Commodore US recently filed for bankruptcy. A buyout of the now-defunct company is pending–you may want to consider Commodore’s uncertain future when selecting a platform.

The Toaster’s four-input switcher has hundreds of wipes, dissolves, and DVEs. It also includes a character generator, dual frame buffers for graphics overlay, a frame grabber and still store, and a 24-bit color paint program.

Perhaps its best feature, however, is Lightwave 3D, one of the most powerful 3D-animation programs available. Many Toaster owners say they bought the Toaster mainly for its 3D capabilities. Its success has been so great that NewTek has announced that this program is now available for Windows. NewTek has also introduced a nonlinear card called Toaster Flyer, which turns the Toaster into a nonlinear editing system. (See next month’s DTV column on nonlinear editing for details.)

The Video Toaster has some drawbacks you should know about if you plan to use it in editing. As a live four-input switcher, the Toaster works fine with genlocked studio cameras (all cameras synchronized or “locked” to the same sync generator signal). Many Toasters perform this function in small TV stations. But if you want to use the Toaster with video tape recorders for editing, or even with more than one live camcorder, each source will need a time base corrector.

The TBC stabilizes the uneven tape signal and synchronizes input signals so frames start at the same instant. This allows you to mix them together. Plug-in card TBCs, such as the two-channel Digital Creations Kitchen Sync, are very popular with Toaster owners.

Another problem: the Video Toaster is not an “Audio Toaster.” It handles only video signals. If you want to dissolve from video track 1 to video track 2 and crossfade from audio 1 to audio 2 at the same time, you’ll need an additional audio mixer.

Edit Control
This brings up the Toaster’s biggest flaw–it lacks edit control. As you saw from the second article in this series, a computer-based edit controller can automate the assembly of your videotape masters. It allows you to flawlessly perform cuts and transitions with special effects. Some editing packages, like the Amilink system from RGB Computer & Video, actually trigger the Toaster during editing.

But if you choose a system like RGB’s Amilink, you’ll be missing one important element in the Desktop Video revolution, the timeline-based interface. Most editing systems still use an interface called an edit decision list (EDL). Each edit event appears as a line with the type of edit (cut, dissolve, wipe, DVE, etc.) and the precise time code of the event start and duration. Time codes for the source tapes and record tapes are both given.

While professional editors are quite familiar with this system, some skill is required in reading an event list. It is not at all easy to get a sense of pace and timing from a list in which clips of different lengths appear as single lines.

In a timeline-based interface (See Videomaker‘s April 1994 Desktop Video column for details), a graphic bar represents each clip of video or audio. The bar’s length indicates the duration of the scene; often the bar displays a recognizable frame from the video clip. The editor simply arranges these bars into a timeline of edit events. The whole process helps you visualize the sequence of scenes.

The two other major computer-based switchers are FAST Electronics’ Video Machine and the Matrox Studio. Both include audio mixing, TBC/frame synchronizers, and timeline-based edit control for two source decks (A/B roll editing).

A Highly Integrated Machine
The FAST Video Machine integrates many functions on a single card. These include a 6-input, 2-bus switcher/SEG with over 300 Sony-compatible transitions and unlimited user-designed effects. It also has two TBC frame synchronizers, so it will synchronize any of the three inputs you select on a bus for mixing with the video from the other bus. Two frame buffers support title/graphic overlays.

The Video Machine can handle a large number of edit protocols–Sony LANC (Control-L), Panasonic 5-pin (Control-M), Sony ViSCA, 25-pin RS232 serial, and 9-pin RS422 serial. It comes with machine control profiles for over 250 decks and camcorders. You can set it up to work with your machines by just choosing their names from a list in a dialog box.

The FAST Video Machine has NTSC/PAL and S-video inputs and outputs. It can function as a standards converter, since it can input NTSC and output PAL signals at the same time. The 8-input audio mixer is organized into four stereo pairs. You can cut or crossfade to another audio track at the same point in the timeline that the video cuts or dissolves.

FAST’s editing software, called VM-Studio, uses a timeline interface like that of the popular Adobe Premiere. It has a Video 1 track and a Video 2 track separated by an FX track. To edit, you simply drag clips and effects from the Project Window and drop them into the timeline. The Video Machine can also display an EDL event list for those who want a list output in standard formats (Sony, CMX, GVG, etc.).

…And Another
Matrox Studio is a multi-card set. It uses separate boards for video input/output, video mixing, effects, and audio. Though it has higher quality effects than the FAST Video Machine, it does not control consumer decks or camcorders. Its machine controls are RS422, with RS232 available as an option.

Both the FAST and Matrox interfaces use the now-standard timeline window, as well as a bin window to hold video and audio clips. Both use the “drag and drop” technique to move clips from icons in the bin window to the timeline track.

But there are differences between the two machines. Matrox uses one clip icon in the timeline, while FAST can show both a “head” and “tail” icon. Neither can show a picture icon for every frame like Adobe Premiere. Both can drop their clips in a “video-style” mode that overwrites the track, or in a “film-style” mode that “ripples” all subsequent clips to later time codes.

The bin windows, Matrox’s “Clip Collections” and FAST’s “Reels” and “Racks,” have database functions for searching and sorting clips. Matrox has a few more comment fields, but FAST’s “Rack” concept makes it a slightly better database. A clip can be in only one Reel, but in more than one Rack for organizing purposes.

Matrox positions their audio tracks (five stereo pairs where the FAST has four) below the video tracks in the timeline, and you can arrange all the tracks in any order you want. Studio also includes Inscriber CG software for titles.

The Video Machine uses any word processing or draw program to create both titles and graphics. You simply “print” the results to the “VM-Titler” for playback in Video Machine. Note that this takes up one of the two video channels in the Video Machine, where the Matrox Studio has an independent graphics track, so you can have graphics over two mixed video sources.

Release 2.0 of Matrox Personal Producer software includes support for an optional CMX-style color-coded keyboard. This allows dozens of direct keyboard operations. This is the keyboard that professional editors have used for years.

What They Cost
The Video Toaster ($2495) is available from dealers installed in an Amiga 4000. You should add in some TBCs and, if you plan to do editing with your Toaster, an edit control systems. A popular approach to audio is to add a digital nonlinear audio editing board, like the AD516 ($1495) from Sunrize Industries.

The Video Machine is available for the PC ($3995) and for the Macintosh ($4995). A new VM Lite version ($2495) costs about the same as the Video Toaster. It has all the important functions of the basic Video Machine, including TBCs, audio, and edit control. Missing are EDL exporting and the Edit Panel, which allows live switching (like the Toaster).

Unless you’re a PC wizard, you should rely on a good dealer to set up your DTV systems. Matrox Studio models are all turnkey systems, which come from the dealer fully configured and guaranteed. The basic model 200 ($12995) is an A/B-roll model with composite and S-video inputs and outputs. The 2000 series has component input/output as well. Model 2200 ($21995) is A/B-roll and 2300 ($24995) is A/B/C roll.

There may soon be another DTV editing system that provides features similar to these three, and then some. At the 1994 National Association of Broadcasters (NAB) show, Digital Creations showed a prototype of what was then called the “V-Machine.” Recently several of the NewTek founders, including Vice President Paul Montgomery and spokesperson Kiki Stockhammer, announced they will join in the marketing of the new product. They will call their joint enterprise Play Digital. At the time of this writing, Play Digital was keeping their work under wraps, but stay tuned and we will review the V-Machine when it comes out.

NewTek, FAST, and Matrox have all announced nonlinear options to work with the switcher/SEG products described here. In next month’s DTV column, we’ll look at digital disk-based nonlinear systems. Once your video signals have entered the computer and been digitized, you can “capture” them onto the DTV computer’s hard disk. The digital video data can be “random accessed” for rapid nonlinear editing, digital playback and recording to videotape. We’ll touch there on these three “hybrid” systems, which combine the economy and image quality of analog videotape with the random access flexibility of digital hard-disk based editing.

One minute of high-quality digital video requires over 100 megabytes of hard-disk storage, which currently costs about $100. By contrast, one minute of analog video on Hi-8 or S-VHS tape costs about ten cents. This enormous economy, coupled with the total absence of digital compression artifacts, makes these hybrid linear/nonlinear systems a good investment for videomakers just getting started with computer-based editing.

The Videomaker Editors are dedicated to bringing you the information you need to produce and share better video.

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